<!DOCTYPE html>
<html>
<head>
	<meta charset="UTF-8">
	<title>1-1-2</title>
</head>
<body>
    
</body>

<script>
    var box=100;
	if(box>=100){
		alert("甲")
	}else if(box>=80){
		alert("丁");
	}else if(box>=70){
		alert("并");
	}else if(box>=60){
		alert("及格");
	}else{
		alert("不及格");
	}
</script>
</html>